My suggestion:
1) Remove all external devices(printer, scanner, etc) except monitor, mouce and keyboard. Remove any device from PCI slots except a video card. Then try installation. If still no go, then
2) Boot to W98 start-up floppy disk, format the hd in FAT32, execute smartdrv.exe(be sure to include smartdrv.exe in this floppy), then begin installation of WXP by executing
a:> X:\i386\winnt.exe
Note X: is the drive name of CDROM drive. Yours may be different.
If still no go, then
3) Suspect RAM. If more than one module are used, try one at a time. Borrow one from other box which you may have, etc.
Kaz